Wildlife officials are asking aquarium owners to destroy their “moss balls” after invasive zebra mussels were found on some of the ornamental plants.
The U.S. Geological Survey warned Monday that the destructive shellfish have been found in pet stores in at least 21 states including Wisconsin.
“The issue is that somebody who purchased the moss ball and then disposed of them could end up introducing zebra mussels into an environment where they weren’t present before,” said Wesley Daniel, the USGS biologist who discovered the problem. “We’ve been working with many agencies on boat inspections and gear inspections, but this was not a pathway we’d been aware of until now.”
The Wisconsin Department of Natural Resources said Thursday the contaminated plants are sold under names including “Betta Buddy Marimo Balls” and “Marimo Moss Ball Plant Grab N Go.”
The DNR is asking retailers to remove all moss balls from shelves and any consumers who have purchased moss balls in the past month to destroy them by freezing, boiling or dunking them in bleach or vinegar before throwing them in the trash.
But do not flush the balls down a drain or toilet, the DNR warns.
Native to the Caspian Sea, the fingernail-sized mollusks can clog pipes, damage boats and wreck beaches and disrupt aquatic ecosystems.
“If it got into the storm sewers, that could do a lot of damage,” said Amy Kretlow, an aquatic invasive species monitoring specialist with the DNR.
In larval stage they are microscopic “veligers” that travel freely in water, while adult zebra mussels can live for several days out of water.
“They’re in the water and you can’t even see them,” Kretlow said. “If the moss balls have adult mussels the water could be contaminated with the veligers and you wouldn’t even know it.”
Moss balls are ornamental plants imported from Ukraine that are often used in aquariums.
According to the USGS, an employee in a Seattle pet store reported seeing a zebra mussel in a moss ball on Feb. 25. Daniel confirmed the discovery and reported it to other federal agencies.
Federal officials realized the problem was widespread after Daniel found a zebra mussel in a moss ball at a pet store in Florida.
USGS and the U.S. Fish & Wildlife Service are coordinating a response with other federal and state agencies as well a pet industry trade group working to get the products off store shelves.
“I think this was a great test of the rapid-response network that we have been building,” Daniel said. “In two days, we had a coordinated state, federal and industry response.”
EDITOR'S NOTE: This story has been updated to correct the spelling of "veligers."